The invention relates to a strand guiding means to be used in a continuous casting plant for supporting, guiding and extracting the cast strand or a starter bar. The strand guiding means is provided with sets of supporting rollers arranged one behind the other in the direction of extraction of the strand. Each set of supporting rollers is provided with a number of rollers located opposite each other and carried by respective roller carrying members also arranged opposite each other, which members are adapted to be adjusted and fixed perpendicular to the surface of the strand. The strand or the starter bar is guided between the respective rollers attached to these members and between the driving rollers provided along the strand guiding means. The driving rollers are adjustable to the strand or the starter bar.
Driving rollers that are adapted to be driven and adjusted to the starter bar and which are arranged between supporting rollers that are merely adjustable to the dimensions of the cross section of the cast strand, prevent an intermittent extraction of the cast strand at the beginning of casting when a wedge-shaped starter bar head tapering in the advancing direction of the strand is used, thus avoiding damage to the cast strand.
In German Auslegeschrift No. 1,758,533 a strand guiding means with drivable pressure rollers adjustable to the smallest cross section of a variety of starter bar heads is described. These pressure rollers are mounted in separate stands, i.e. stands separate from the stands of the supporting rollers. The pressure forces acting upon the pressure rollers are relieved adjacent a pressure roller as soon as the starter bar head of the starter bar approaches such pressure roller and the respective pressure roller is adjusted to the size of the cast strand. All of the roller running surfaces facing the strand must be in precise alignment, so as to avoid any unnecessary deformation of the strand and thus an increased extraction force or even cracks in the strand skin. A disadvantage of the construction described in German Auslegeschrift No. 1,758,533 consists in that it is difficult to carry out a precise adjustment to the thickness of the cast strand of the pressure rollers mounted in separate stands and independent of the supporting rollers. A further disadvantage is seen in that any change in the strand thickness necessitates a re-adjustment of not only the position of the supporting rollers, but also the position of the pressure rollers.